// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_AURA_WINDOW_DELEGATE_H_
#define UI_AURA_WINDOW_DELEGATE_H_

#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"
#include "ui/aura/aura_export.h"
#include "ui/events/event_constants.h"
#include "ui/events/event_handler.h"
#include "ui/gfx/native_widget_types.h"

namespace gfx {
class Canvas;
class Path;
class Point;
class Rect;
class Size;
}

namespace ui {
class GestureEvent;
class KeyEvent;
class Layer;
class MouseEvent;
class PaintContext;
class TextInputClient;
class Texture;
class TouchEvent;
}

namespace aura {

// Delegate interface for aura::Window.
class AURA_EXPORT WindowDelegate : public ui::EventHandler {
public:
    // Returns the window's minimum size, or size 0,0 if there is no limit.
    virtual gfx::Size GetMinimumSize() const = 0;

    // Returns the window's maximum size, or size 0,0 if there is no limit.
    virtual gfx::Size GetMaximumSize() const = 0;

    // Called when the Window's position and/or size changes.
    virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
        const gfx::Rect& new_bounds)
        = 0;

    // Returns the native cursor for the specified point, in window coordinates,
    // or NULL for the default cursor.
    virtual gfx::NativeCursor GetCursor(const gfx::Point& point) = 0;

    // Returns the non-client component (see hit_test.h) containing |point|, in
    // window coordinates.
    virtual int GetNonClientComponent(const gfx::Point& point) const = 0;

    // Returns true if event handling should descend into |child|. |location| is
    // in terms of the Window.
    virtual bool ShouldDescendIntoChildForEventHandling(
        Window* child,
        const gfx::Point& location)
        = 0;

    // Returns true of the window can be focused.
    virtual bool CanFocus() = 0;

    // Invoked when mouse capture is lost on the window.
    virtual void OnCaptureLost() = 0;

    // Asks the delegate to paint window contents into the supplied context.
    virtual void OnPaint(const ui::PaintContext& context) = 0;

    // Called when the window's device scale factor has changed.
    virtual void OnDeviceScaleFactorChanged(float device_scale_factor) = 0;

    // Called from Window's destructor before OnWindowDestroyed and before the
    // children have been destroyed and the window has been removed from its
    // parent.
    // This method takes the window because the delegate implementation may no
    // longer have a route back to the window by the time this method is called.
    virtual void OnWindowDestroying(Window* window) = 0;

    // Called when the Window has been destroyed (i.e. from its destructor). This
    // is called after OnWindowDestroying and after the children have been
    // deleted and the window has been removed from its parent.
    // The delegate can use this as an opportunity to delete itself if necessary.
    // This method takes the window because the delegate implementation may no
    // longer have a route back to the window by the time this method is called.
    virtual void OnWindowDestroyed(Window* window) = 0;

    // Called when the TargetVisibility() of a Window changes. |visible|
    // corresponds to the target visibility of the window. See
    // Window::TargetVisibility() for details.
    virtual void OnWindowTargetVisibilityChanged(bool visible) = 0;

    // Called from Window::HitTest to check if the window has a custom hit test
    // mask. It works similar to the views counterparts. That is, if the function
    // returns true, GetHitTestMask below will be called to get the mask.
    // Otherwise, Window will hit-test against its bounds.
    virtual bool HasHitTestMask() const = 0;

    // Called from Window::HitTest to retrieve hit test mask when HasHitTestMask
    // above returns true.
    virtual void GetHitTestMask(gfx::Path* mask) const = 0;

protected:
    ~WindowDelegate() override { }
};

} // namespace aura

#endif // UI_AURA_WINDOW_DELEGATE_H_
